Proteincalorie malnutrition (PCN) has been shown in multiple studies to be present in 1 of 3 hospital admissions to a surgical service; and upwards of 40% of emergency surgical admissions. Surgical procedures in these groups carry a significantly high mortality and morbidity risk, particularly for cardiac and pulmonary complications. Acquired PCM is also a common disease, particularly in Intensive Care Units. Again, cardiac and pulmonary problems are a prominent feature. Nutritional repletion of the severly malnourished patient is also associated with cardiac or cardiopulmonary failure. The precise reaction of the heart to nutritional depletion and repletion is poorly known and studied. The present study is designed to evaluate this problem in a chronic, awake canine model. Cardiac function will be assessed by sonomicrometry in a setting of chronic nutritional depletion and repletion. Detailed assessment of myocardial contractile function will be done periodically in this sophisticated proven surgical model at rest and under surgically simulated stress induced by pacing, temperature and exercise. Along with this will be biopsies, BMR and nutritional indices. Nutritional depletion will occur over 60 days on a defined prescribed diet supplying 7.5 Kcal/Kg/day, along with a control receiving 67 Kcal/kg/day. Repletion will then occur on defined diets of control, high carbohydrates, high fat on high protein; with periodic assessment of the same parameters. Thus, the effects of malnutrition on ventricular function at rest and under surgical stress; and the effects of regimens of nutritional repletion; will be quantitatively assessed in a chronic conscious canine surgical model.